|Table of Contents|

Comprehensive analysis of fractal and wavelet packet of acoustic emissionsignal in process of concrete bridge crack propagation(PDF)

长安大学学报（自然科学版）[ISSN:1006-6977/CN:61-1281/TN]

Issue:
2021年2期
Page:
34-45
Research Field:
桥梁与隧道工程
Publishing date:

Info

Title:
Comprehensive analysis of fractal and wavelet packet of acoustic emissionsignal in process of concrete bridge crack propagation
Author(s):
YUAN Ming1;  CHENG Xiaodong1;  HUANG Lian1;  YAN Donghuang1;  LIU Yun1; 2
（1. School of Civil Engineering, Changsha University of Science & Technology, Changsha 410114,Hunan, China; 2. School of Road and Bridge Engineering, Hunan CommunicationPolytechnic, Changsha 410132, Hunan, China)
Keywords:
bridge engineering;  concrete bridge;  crack propagation;  AE signal;  waveform fractal;  frequency spectrum characteristic;  wavelet packet decomposition
PACS:
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DOI:
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Abstract:
In order to quantify the change rule of acoustic emission (AE) signal from microscopic initiation to macroscopic expansion of concrete bridge cracks, an AE test of concrete cablestayed bridge model was carried out. The fractal box dimension, main frequency evolution rule, frequency band energy distribution characteristics and fractal box dimension evolution rule of AE signal in the experiment were analyzed comprehensively by using waveform fractal calculation method, FFT transform and wavelet packet decomposition method. And then the fractal and spectrum evolution characteristics of AE signal in the crack propagation process of concrete bridge were studied. The results show that the fractal box dimension of AE signal waveform generated by macro cracks is larger than that generated by micro cracks during crack propagation of concrete bridge, and the former has a wider distribution range and relatively more complex waveforms. During the crack propagation process of concrete bridge, AE signals generated at the microcrack initiation stage are dominated by medium and low frequency signals, while AE signals generated at the macro crack stage are dominated by medium and high frequency signals. During the static loading process of the concrete cablestayed bridge model, all AE signal energy is concentrated in 0 to 234.375 kHz. During the initiation and development of concrete microcracks, AE signal energy is mainly distributed in the low and medium frequency bands of 0 to 125 kHz, and gradually evolves to the middle and high frequency bands with the loading process. The collected AE signals in the test are decomposed by wavelet packet change method. The fractal box dimension of the reconstructed signal fluctuates and rises as the frequency increases in the 0 to 265.625 kHz frequency band. This rising trend shows a thirdorder polynomial change, the thirdorder fitting error is smaller, and the regularity is better in the macrocrack stage of concrete, compared with that in the microcrack stage of concrete. The size of the signal fractal box can be used to reflect the signal frequency. 4 tabs, 16 figs, 33 refs.

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Last Update: 2021-04-02